li.netcat.chart.data
Interface StackModel

The StackModel adapts a chart model and calculates the lead and the
tail of each numeric value in the model. Imagine a stacked bar chart: Each
cell in the model gets its bar and each bar starts at a certain value
(=trail) and ends at a certain value (=lead). In a line chart, only the
lead values are of interest.

The strategy of a stack model defines how negative values get handled.